Java 中的 Reader read(char[])方法，示例

原文:https://www . geesforgeks . org/reader-read char-method-in-Java-with-examples/

Java 中 Reader 类的 read(char[]) 方法用于将指定的字符读入数组。这个方法阻塞流直到:

  • It takes some input from the stream.
  • Some IOException occurred.
  • It has reached the end of the stream when reading.

语法:

public int read(char[] charArray)

参数:该方法接受一个强制参数字符数组，它是要写入流中的字符数组。

返回值:该方法返回一个整数值，即从流中读取的字符数。如果未读取任何字符，则返回-1。

异常:如果输入输出时出现错误，该方法抛出异常。

下面的方法说明了 read(char[])方法的工作原理:

程序 1:

// Java program to demonstrate
// Reader read(char[]) method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            String str = "GeeksForGeeks";

            // Create a Reader instance
            Reader reader
                = new StringReader(str);

            // Get the character array
            // to be read from the stream
            char[] charArray = new char[5];

            // Read the charArray
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            reader.read(charArray);

            // Print the read charArray
            System.out.println(
                Arrays
                    .toString(charArray));

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

[G, e, e, k, s]

程序二:

// Java program to demonstrate
// Reader read(char[]) method

import java.io.*;
import java.util.*;

class GFG {
    public static void main(String[] args)
    {

        try {

            String str = "GeeksForGeeks";

            // Create a Reader instance
            Reader reader
                = new StringReader(str);

            // Get the character array
            // to be read from the stream
            char[] charArray
                = new char[str.length()];

            // Read the charArray
            // to this reader using read() method
            // This will put the str in the stream
            // till it is read by the reader
            reader.read(charArray);

            // Print the read charArray
            System.out.println(
                Arrays
                    .toString(charArray));

            reader.close();
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

[G, e, e, k, s, F, o, r, G, e, e, k, s]

参考:https://docs . Oracle . com/javase/9/docs/API/Java/io/reader . html # read–

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